"Did you find $5?" is a question you ask someone when they tell you a ridiculously pointless story. The reason you ask this is because it's comparable to someone saying to you, "So I found $5 today!" and you're like, ...sweet.

Bill: "Yeah, so this girl texted me once and she was like, your number is easy to remember cause it's close to my best friend's, and I was like whoa yeah!"
Tom: "Cool, did you find $5?"
Bill: "...."